The present invention relates to a multilayered body for photolithographic patterning or, more particularly, to a multilayered body for photolithographic patterning of a resist layer comprising a substrate, a first anti-reflection coating film formed on the surface of the substrate, a layer of a specific negative-working photoresist composition on the first anti-reflection coating film and, optionally, a second anti-reflection coating film formed on the resist layer and suitable for obtaining, with high photosensitivity, a patterned resist layer of high pattern resolution having excellently orthogonal cross sectional profile with little edge roughness.
Along with the trend in recent years toward higher and higher degree of integration in various semiconductor devices, the photolithographically patterned resist layer on a substrate surface is required to have a pattern resolution of as fine as 250 nm or, as a target in the coming generation, as fine as 200 nm. Needless to say, such an extremely fine pattern resolution of the patterned resist layer cannot be accomplished without an innovative improvement in the performance of the photosensitive patterning material which may be a photosensitive material for patterning of a chemical-amplification negative-working photoresist layer.
The above mentioned chemical-amplification negative-working photoresist composition is typically formulated with an acid-curable alkali-soluble resin such as a phenolic resin, a radiation-sensitive acid-generating agent and a crosslinking agent for the resin such as an addition product of urea or melamine and formaldehyde. It is usual that a photoresist layer of a chemical-amplification negative-working photoresist composition is formed not directly on the surface of a substrate but on an undercoating layer of an anti-reflection film of a water-insoluble anti-reflection compound formed on the substrate surface in view of the advantage relative to the pattern resolution which can be as fine as 200 nm or even finer.
It is sometimes the case, however, that, when a conventional chemical-amplification negative-working photoresist composition is used in combination with an anti-reflection coating film including organic films formed from the most typical commercial products of the DUV Series (each a product by Brewer Science Co.) as well as inorganic anti-reflection coating films, an excellently orthogonal cross sectional profile of the patterned resist layer can hardly be obtained and the cross sectional profile is more or less trapezoidal or skirt trailing. Accordingly, it is one of the target problems in the development works for negative-working photoresist compositions to obtain a chemical-amplification negative-working photoresist composition capable of being used in combination with an anti-reflection coating film without being influenced in the pattern resolution and cross sectional profile of the patterned resist layer.
It is sometimes the case that formation of a resist pattern is accompanied by an undesirable phenomenon of “edge roughness”, especially, when the resist pattern width is extremely fine to be 200 nm or smaller.
It is known according to the disclosure in Japanese Patent No. 2878150, on the other hand, that, when a photo-resist layer of a positive-working or negative-working photoresist composition of the chemical-amplification type is provided thereon with an anti-reflection film of a water-soluble anti-reflection compound, an improvement in the pattern resolution and suppression of the adverse influences of standing waves can be accomplished.
Although it is a possible way that a substrate surface is provided with three coating layers successively consisting of a first anti-reflection film of a water-insoluble anti-reflection compound, a photoresist layer and a second anti-reflection film of a water-soluble anti-reflection compound, the photolithographic patterning work by using such a patterning material cannot be very efficient because both of the steps for removal of the water-soluble anti-reflection film and etching of the water-insoluble anti-reflection film. Accordingly, it is usual in the manufacturing process of semiconductor devices in which a very high throughput of the products is essential that the photolithographic patterning material has a two-layered coating on the substrate consisting either of a water-insoluble anti-reflection film and a photoresist layer thereon or of a photoresist layer and a water-soluble anti-reflection film thereon.
A patterning material having a two-layered coating consisting of a negative-working photoresist layer and a water-soluble anti-reflection film thereon has a problem that an unnecessary crosslinking reaction proceeds at or in the vicinity of the interface between the two coating layers eventually resulting in a T-formed cross sectional profile of the patterned resist layer. While it is eagerly desired to obtain a patterned resist layer having excellently orthogonal cross sectional profile, in addition, attention in the development works is now switched to a patterning material of the three-layered coating from which a patterned resist layer having an excellently orthogonal cross sectional profile by overcoming the problems of a skirt trailing cross sectional profile at the interface between the water-insoluble anti-reflection coating film and the photoresist layer and a T-formed cross sectional profile at the interface between the photoresist layer and the water-soluble anti-reflection film thereon.